Khan.scratchpad.disable(); Tiffany sells magazine subscriptions and earns $$8$ for every new subscriber she signs up. Tiffany also earns a $$30$ weekly bonus regardless of how many magazine subscriptions she sells. If Tiffany wants to earn at least $$71$ this week, what is the minimum number of subscriptions she needs to sell?
Solution: To solve this, let's set up an expression to show how much money Tiffany will make. Amount earned this week $=$ $ $ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus Since Tiffany wants to make at least $$71$ this week, we can turn this into an inequality. Amount earned this week $\geq $71$ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus $\geq $71$ We are solving for the number of subscriptions sold, so let subscriptions sold be represented by the variable $x$ We can now plug in: $x \cdot $8 + $30 \geq $71$ $ x \cdot $8 \geq $71 - $30 $ $ x \cdot $8 \geq $41 $ $x \geq \dfrac{41}{8} \approx 5.13$ Since Tiffany cannot sell parts of subscriptions, we round $5.13$ up to $6$ Tiffany must sell at least 6 subscriptions this week.